This invention generally relates to a braided suture and a process for producing a braided suture. More specifically the present invention discloses a process for producing a braided suture with improved knot strength.
Braided multifilament sutures are commonly used in surgery because of their excellent flexibility and handling properties. Braided sutures are generally used because an equivalent monofilament suture of the same material would be too stiff to be used as a suture. However, braiding creates inherent limitations in the properties of the final suture. For example braided sutures generally have rougher surfaces and may have lower overall straight and knot tensile strengths as compared to a monofilament suture of the same size. To improve the surface characteristics of braided sutures the surface of these sutures are generally coated with a lubricant to avoid the undesirable side effects of suture roughness (i.e. excessive tissue abrasion as the suture is passed through tissue) and difficulty in sliding down knots as the surgeon secures the suture in place. Suture coatings can be applied by a variety of methods. It is typical however, that they are applied by drip coating or dip coating the suture with a film-forming polymer suspended in or dispersed in a volatile solvent. The coated suture is then dried by passing the suture through a drying oven. Although coating the braided suture solves many of the issues associated with surface roughness it does not address how to improve the tensile strengths of braided sutures, particularly the knot tensile strength.
To overcome the limitations imposed by braided sutures Hunter and Rosen proposed in U.S. Pat. No. 3,791,388 to construct a multifilament yarn impregnated with an adhesive binder covered with a ribbon like helical winding. The Hunter-Rosen suture had a higher knot strength compared to conventional coated braided sutures. Unfortunately little further research has been done to develop braided sutures with improved knot strengths.
It is an object of the present invention to provide a process for producing a braided multifilament suture with an improved knot strength. A further object of the present invention is to provide a braided suture with an improved knot strength.
We have discovered a process for producing a braided suture having an improved knot strength comprising heating a braided suture coated with a biocompatible polymer to a temperature sufficient to melt the biocompatible polymer for a time sufficient to allow the polymer to be redistributed into the interstices of the braided suture thereby providing a coated braided suture with an improved knot tensile strength.
In a further embodiment of the present invention we have also discovered a coated braided suture with an improved knot strength comprising a braided suture having a biocompatible polymer dispersed throughout the braided suture.
These and other objects and advantages of the present invention will be apparent to one of skill in the art from the following Drawings, Detailed Description, Examples and claims.